The Three-Phase Mains with Neutral Monitoring Relay is designed to monitor and protect electrical systems. It offers features such as overvoltage and undervoltage protection, phase sequence monitoring, phase asymmetry detection, and phase failure detection.The upper adjustable level of voltage (Umax) ranges from AC 138V to 276V, while the bottom adjustable level of voltage (Umin) ranges from 30% to 99% of Umax.This relay has two output contacts that can operate independently or in parallel. It also includes a memory function and a 'RESET' button on the front panel.There is a time delay of 0-10 seconds for both Umax and Umin settings.The relay has two changeover contacts with a rating of 16 A at 230 VAC supply voltage.In terms of size, it occupies three width 17.5 mm modules.